EOIFP Block Versus OSTAP Block for Upper Abdominal Surgery

With the OSTAP block, local anesthetic is injected into the fascial plane between the posterior rectus sheath and the transversus abdominis muscle beneath the subcostal margin.

With the EOIF block, local anesthetic targets the terminal part of the thoracoabdominal nerves pass behind the costal cartilage and continue anteriorly in the plane between the internal oblique and transversus abdominis muscle, before piercing the rectus abdominis sheath as anterior cutaneous branches supplying the skin of the midabdomen.